Most plants prefer a root zone temperature of 18 - 22 °C (65 - 72 °F)

Cooler for winter crops, warmer for tropical crops.

Keep your solution at around 20ºC (68ºF) for the best oxygen content and uptake by the roots. High water temperature (above 22ºC or 72ºF) quickly reduces dissolved oxygen and increases the risk of root disease. Cold water temperature can shock roots and cause other problems.

Adding water to your reservoir?

Get it to the same temperature as the root zone water before you start the pumps. Rapid changes to the temperature of the solution will stress plants.

Tips for controlling solution temperature:

In winter: Put a heat mat under your reservoir and/or use aquarium heaters for your nutrient.

In summer: Use chillers.

Protect your solution from direct sunlight: Insulate it or sink your reservoir in the ground.

Reducing direct light on the solution will also slow or prevent the growth of algae and bacteria: If you’re growing indoors, be aware of the heat from plant lamps. A slight change in a light’s position can make a big difference to growth. Outdoors, or in a greenhouse, the amount of sunlight will affect the temperature of your growing environment.

Keep a close eye on the temperature of your solution

Bluelab meters have easy to read LCD screens. Our meters measure temperature in Celcius or Fahrenheit - simply choose the units you need, or change them as you go.

For small hydroponic sytems or beginner growers, the handy pens range or one of our portable meters will give you accurate measurements from the palm of your hand.